title: Urinary stone detection and characterisation with dual-energy CT urography after furosemide intravenous injection: preliminary results.
abstract: OBJECTIVE
  To investigate the added advantage of IV furosemide injection and the subsequent urine dilution in the detection of urinary calculi in the excretory phase of dual-source dual-energy (DE) computed tomography (CT) urography, and to investigate the feasibility of characterising the calculi through diluted urine.
  
  
  METHODS
  Twenty-three urinary calculi were detected in 116 patients who underwent DECT urography for macroscopic haematuria with a split bolus two- or three-acquisition protocol, including a true unenhanced series and at least a mixed nephrographic excretory phase. Virtual unenhanced images were reconstructed from contrast-enhanced DE data. Calculi were recorded on all series and characterised based on their X-ray absorption characteristics at 100 kVp and 140 kVp in both true unenhanced and nephrographic excretory phase series.
  
  
  RESULTS
  All calculi with a diameter more than 2 mm were detected in the virtual unenhanced phase and in the nephrographic excretory phase. Thirteen of these calculi could be characterised in the true unenhanced phase and in the mixed nephrographic excretory phase. The results were strictly identical for both phases, six of them being recognised as non-uric acid calculi and seven as uric acid calculi.
  
  
  CONCLUSIONS
  Mixed nephrographic excretory phase DECT after furosemide administration allows both detection and characterisation of clinically significant calculi, through the diluted urine.
  
  
  CONCLUSIONS
  • Urinary tract stones can be detected on excretory phase through diluted urine. • Urinary tract stone characterisation with dual-energy CT (DECT) is possible through diluted urine. • A dual energy split-bolus CT urography simultaneously enables urinary stone detection and characterisation.
authors.affiliation: Radiology Department, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland, diomidis.botsikas@hcuge.ch.
authors.forename: Diomidis
authors.initials: D
authors.lastname: Botsikas
authors.forename: Catrina
authors.initials: C
authors.lastname: Hansen
authors.forename: Salvatore
authors.initials: S
authors.lastname: Stefanelli
authors.forename: Christoph D
authors.initials: CD
authors.lastname: Becker
authors.forename: Xavier
authors.initials: X
authors.lastname: Montet
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D004232:Diuretics / Q000008:administration & dosage; D005240:Feasibility Studies; D005260:Female; D005665:Furosemide / Q000008:administration & dosage; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014545:Urinary Calculi / Q000000981:diagnostic imaging* / Q000652:urine; D014567:Urography / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D004232:Diuretics; D005665:Furosemide